This study intended: to assess use cone-beam analysis of gutta percha removal by Reciproc versus ProTaper Universal retreatment systems.Methods: Thirty extracted humanoid lower first molars were collected. The mesiobuccal canals had been mechanically prepared in a crown-down approach using the "TF Adaptive" setting on Elements Motor. TF Adaptive Green ML1 file (Medium Large) and Yellow ML2 size 35 taper 4% till the file gets to the effective length. the obturation was done by lateral condensation technique with gutta pearch size 35 taper 6%, and AH plus in the same visit, and using gutta pearch size 25 taper 2% as auxiliary cones with spreader size 25. samples were unintentionally split into two investigational groups concurring to the re-treatment method used (n = 15). Group I: Reciproc system, and Group II: ProTaper Universal re-treatment. Cone beam (CBCT) was used to evaluate the gutta percha removal in both groups.Results: little left guttapercha after the wastage of Reciproc kit (0.169mm 3 ) afterwards the Pro Taper kit(1.459 mm 3 ). There were little left gutta percha after the use of the Reciproc system (The rate of decrease was 96.82 %) followed by the ProTaper Universal re-treatment kit (The rate of decrease was 76.17 %). Conclusions:Reciproc was more effective than Protaper Universal kit in the elimination of resin sealers like epoxy based sealers and the guttapercha through re-treatment.

This study aimed to: evaluate the antibacterial efficacy of two natural irrigating solutions (Green Tea, and Propolis) with two different root canal sealers (AH Plus sealer, and Total Fill BC Sealer) against E. faecalis. Methods: One hundred single rooted teeth were selected. All root canals were prepared manually to #50 file. Finally the teeth were sterilized by gamma rays. Each root canal was inoculated with 0.5 ml of E.faecalis. Specimens were divided randomly into two main groups (50 specimens each) according to the irrigating solution; A1 (Green Tea), and A2 (Propolis). Each main group was divided into two subgroups with (25 specimens each) according to the type of sealer used B1 (AH Plus sealer), and B2 (TotalFill BC Sealer). The bacterial sampling counting process was done three times throughout the study. Five specimens from each subgroup were examined by SEM for presence or absence of E. faecalis. Results:The highest mean value of bacterial count was found in (Green tea) (6.50x10x10 ± 1.29x10x10) while the least mean value of bacterial count was found in (Propolis) (with less antibacterial effect 2x10x10 ± 1.33x10x10) with higher antibacterial effect. The highest mean value of bacterial count was found in (AH Plus Sealer) (5.40x10x10 ± 2.44x10x10) with less antibacterial effect while the least mean value of bacterial count was found in (TotalFill BC Sealer) (3.10x10x10 ± 1.54 x10x10) with higher antibacterial effect. Conclusions: Propolis is an effective intracanal irrigant in eradicating E.faecalis. On other hand TotalFill BC Sealer is more effective in reducing E. faecalis.

Background: An untreated root canal is one of the main causes of failure in endodontics. The aims of this study were to detect the middle mesial canals (MMCs) prevalence in mandibular 1st molars, its configuration type, and its percentage of incidence with age by Cone-Beam Computed Tomography (CBCT) analysis.Methods: CBCT scan of 1650 patients were observed between January 2021 to February 2022 were collected using the CBCT imaging system from the database of the department of oral radiology, faculty of dental medicine, Al-Azhar university - Assiut branch. CBCT scan images were analyzed by Sidexis software. CBCT images were examined to detect the following: (1) The percentage of incidence frequency of the MMCs, (2) MMCs classification, and (3) Frequency of occurrence of MMCs according to age. Results: The incidence frequency percentage of the presence of MMCs among the Egyptian population was 10.79 % (208/1926) with no statistically significant due to gender, While MMCs configuration types showed 77% (160/208) confluent anatomy merging with either the mesio buccal or mesio lingual canals, 16.3% (34/208) fin anatomy and only 6.7% (14/208) showed independent MMCs with separate orifices and apical foramen. lastly the incidence frequency percentage of the presence of MMCs decreases with age. Conclusions: The MMCs prevalence in mandibular 1st molars among some Egyptian population was 10.79 %, and CBCT scan is helpful way to detect the presence of MMCs.

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Aim: The study was done to evaluate the antibacterial effect of a new formula of Salvadora persica roots Nanoparticles as compared to sodium hypochlorite irrigating solution. Methods: A total of 20 recently extracted single-rooted, with single root canal were selected to be used in the study. Decapitation of the selected teeth for 18 mm length standardization was done. The root canals were initially instrumented using manual instrumentation till reach file size 25 for apical preparation. Sterilization of the samples was done using gamma rays. Following sterilization, the samples were divided into two groups (n=10) according to the tested irrigating solution used as follow; Group H: For Salvadora persica roots nanoparticles. Group S: For 2% sodium hypochlorite. The chemo-mechanical preparation was accomplished using Revo-S rotary system in a crowndown technique with the file sequence that was recommended by the manufacturers. Pre and postirrigation counting of the E. Fecalis was done by determining the Colony Forming Unit. Results: The highest mean value of percentage changes in bacterial reduction was found in (Group S) (95.99%) and the least bacterial reduction percentage was found in (Group H) (82.83% with no statistically significant difference between both groups (P-value=0.068). Conclusion: Under the condition of this study, the new formula of Salvadora persica roots nanoparticles is a promising irrigating solution of herbal origin instead of the synthetic irrigating solution.